A cataract is an opaque portion of the lens of the eye. A cataract can be localized to a small region of the lens or it can be diffuse wherein the entire lens appears cloudy. It is the primary cause of visual impairment worldwide, and also the leading cause of vision loss in the United States. An estimated 20.5 million Americans aged 40 years and older have a cataract in one or both eyes. This number is expected to increase to 30.1 million by 2020.
Cataracts can occur at any age and can be present at birth. Causes of cataracts include age, heredity, trauma, inflammation, metabolic disorders, smoking, alcohol consumption, nutritional deficiencies, certain medications, and ultra-violet radiation. Fortunately, cataract surgery is available to reduce this visual impairment.
Cataract surgery involves removal of the entire eye lens with concomitant replacement of the lens with an artificial lens. According to the WHO, the number of cataract surgeries performed in 2010 was estimated to be around 20 million and this number is expected to reach 32 million by 2020. About 3 million cataract surgeries are performed each year in the U.S. alone, making it the most common surgery for Americans over age 65. The amount spent on cataract surgeries in the U.S. is several billion dollars per year.
Proper post-operative care is critical to ensure an optimal visual outcome after cataract surgery. It is during the period of post-operative care that most complications occur, such as bacterial infection, uncontrolled elevated intraocular pressure (IOP), ocular hypertension, malignant glaucoma, wound leakage, cystoid macular edema (CEM), endophthalmitis, iris prolapse, intraocular lens dislocation, hemorrhage, and severe inflammation. The post-operative regimen normally includes restricted activity and the application of a multitude of topical medications to the eye at numerous times per day for 1-8 weeks depending on the patient's situation and the nature of the surgery. These topical medications generally include an antibiotic to be applied 1-4× per day; a steroidal agent to be applied 1-4× per day, and/or a non-steroidal agent to be applied 1-4× per day, with a 5 minute gap between the application of the each medication to the eye. The time gap between doses helps to diminish the likelihood that the first dose will be washed out by the second dose because of insufficient time for absorption of the first dose.
Most people, especially the elderly who undergo the majority of cataract surgeries, experience difficulty in complying with such a complicated medication regimen. For example, it is difficult for some people to put drops in their eyes, which is amplified by the need to do so four times a day with three separate solutions for a total of 1-8 weeks. As mentioned above, there is a problem wash out of the first medicine by application of the second medicine if the required wait time is not adhered to. Another problem is that one or more of the three bottles may be misplaced, contaminated, or damaged. Yet another problem is the difficulty in keeping track of which medicine was already instilled in the eye when there are three bottles of medicine to be used in one sitting. Still another problem is that the length of time the medicating process takes is long because there is a wait time of 5 minutes after each drop is instilled, which process totals about an hour a day devoted to instilling drops to the eye. Also, another problem is that attempts at combining a quinoline antibiotic with an anti-inflammatory agent results in formulations containing a precipitate and/or particulate matter as in a suspension so that there are none commercially available as an aqueous solution.
Thus, there is an urgent need for an easier-to-follow medication regimen in order to increase patient compliance and to ensure better visual outcomes. The composition described in this application solves this problem by combining all three previously separate medications into a single, homogeneous solution, which will be significantly less complicated for the patient to use and will result in better compliance and visual outcomes.
Unexpectedly, preliminary results indicate that use of the composition described herein, which contains all of the active ingredients within one solution, seems to reduce the incidence of cystoid macular edema (CME) more effectively than the use of separate solutions of each of the active ingredients. CME is the most prevalent cause of vision loss after cataract surgery, with up to 58% of patients having some angiographic evidence of CME and there is no reliable treatment for the prevention or treatment of CME following cataract surgery.